Casted concrete blocks have a rectangular configuration in which the surfaces are substantially planar with adjacent surfaces delimited by sharp edges.
It has been known to treat the concrete blocks in order to get a more natural rough look which is typical of an authentic stone block.
Various apparatuses have been devised in order to provide this rough surface appearance to concrete casted blocks. For example, U.S. Pat. No. 6,561,786 issued May 13, 2003 and U.S. Pat. No. 6,575,727 issued Jun. 10, 2003, both in the name of Techo-Bloc Inc. describe an apparatus for roughing surfaces of concrete casted blocks wherein the surfaces to be roughened are impacted by means of chain links attached to a disk rotatably driven by a drive shaft. Means are provided to mount the blocks so that the chain links may abrade the edges of the blocks. Another apparatus is described in U.S. Pat. No. 6,109,906 to Castonguay et al. for treating concrete blocks and includes flails mounted to a drive shaft which is adapted to rotate in opposite directions provide a balanced distribution of impacts at the corners of the blocks.
It has been found that the devices described in the prior art provide, through a chiseling effect, an abrasion of the edges of the blocks causing them to burst.